HALME. 



159 



iiiillim. in diameter, and are cemented by spongin. The cortex has a thickness 

 of about 0-35 millim. The canals leading into the vestibular lacunae are short 

 and circular, cylindrical perforations of the external lamella. In their walls 

 the layer of sand-grains is only half as thick as on the outer surface. As we 

 proceed downward, the size of the sand-grains and the thickness of the cortex 

 decrease rapidly, until in the interior the sand-grains measure only 0-02 

 millim. in diameter and the cortex 0-05 millim. in thickness. We must 

 assume that the sponge exerts some active influence on the selection and 

 distribution of the sand-grains. 



Geographical Distribution.— South coast of Australia : Port Phillip, V. 

 (Lendenfeld). East coast of Australia : Port Jackson, N. S. W. {LendenfdJ) ; 

 Port Stephens, N. S. W. {Ramsay). 



Halme micropora, Lendenfeld. 



Ilahnemicropora, R. v. Lendenfeld, " A Monograph of the Australian Sponges. 



—Part V. The AuleninsB," Proceedings of the Linnean Society of New 



South Wales, vok x. p. 304 (1885). 

 Holopsamma lamincvjavom (partim), H.J.Carter, " Descriptions of Sponges 



from the Neighbourhood of Port Phillip Heads, South Australia," Annals 



and Magazine of Natural History, ser. 5, vol. xv. p. 212 (1885). 



Massive, irregular, globose, or cup-shaped sponges, which attain a breadth of 

 70 millim. and a height of 40 millim. The sponge consists of an irregular 

 honeycomb-like reticulation. There is no dermal lamella, but the outermost 

 cells of the honeycomb are distally closed by thin membranes, which are per- 

 forated by small holes. These membranes are concave, and occupy the depressed 

 polygonal areas which lie between the network formed by the free margins of 

 the lamellfe. There are also membranes in the very regular, radially situated 

 cells of the honeycomb. The living sponge is bright yellow ; preserved and 

 dried specimens "are light grey. The sponge is hard and incompressible, the 

 surface is protected by an arenaceous cortex. 



The supporting slcdeton consists of irregular rows of sand-grains about 

 0-15 millim. in size, which are not in contact with each other, and appear 

 connected by very fine unbranched spongin-fibres. 



Geographical Distribution.— East coast of Australia : Illawarra, N. S. W. 

 {Uamsarj). 



